1. For. 485: Lignocellulosic Composite Materials
Lecture 1-4: Viscoelastic Behavior of Wood

2. Viscoelasticity A viscoelastic material is one in which:
hysteresis is seen in the stress-strain curve.
stress relaxation occurs: step constant strain causes decreasing stress
creep occurs: step constant stress causes increasing strain
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3. Viscoelasticity of Lignocellulosics
Attributable to the multicomponent polymer system comprising the cellular solid
Is manifested in thermo-compression processes
FPL-GTR-149

4. OSB “mattress” or mat undergoing increasing compressive strain

5. Stress-strain diagram for a wood particle mat under compression

6. For more information…
…See the handout to accompany this discussion…an excerpt from Forest Products Lab General Technical Report, FPL-GTR-149 (source of the diagrams in this lecture)
Complete publication is available at: